Molten metal feeding tube for metal casting machines



June 23, 1964 MQRTQN 3,137,903

MOLTEN METAL FEEDING TUBE FOR METAL CASTING MACHINES Filed. Feb. 13,1961 2 Sheets-Sheet 1 IN V EN TOR.

616M 14 MOFfO/V June 23, 1964 MORTON 3,137,903

MOLTEIN METAL FEEDING TUBE FOR METAL CASTING MACHINES Filed Feb. 15.1961 2 Sheets-Sheet 2 INVEN TOR.

Git M16 MOET 0 BY F" M (i Mow/97v 6. 7697/86 United States Patent3,137,963 MGLTEN METAL FEEDENG TUBE FOR METAL CASTING MACHINES Glenn R.Morton, 7025 Sarpy Ave., Omaha, Nebr. Filed Feb. 13, 1961, Ser. No.88,873 8 Claims. (Cl. 22-68) This invention relates to material feedingtubes for casting machines and especially to a molten metal supply tubefor metal casting devices.

Metal casting is an old art. However, modern times require highlyefiicient machines that are at least semiautomatic. Electricallycontrolled vacuum type machines have solved many problems present involume casting. However, much trouble is still experienced in the metalfeeding tube or conduit that passes the molten material into the shotcylinder or into the mold cavity. Firstly, the molten metal betweenintermittent supply flows, tends to solidify onto the walls of thefeeding tube. Secondly, the feeding tube transfers objectionable heat tothe shot cylinder and its ram piston. Thirdly, and perhaps moreimportant, the molten mass tends to stratify both as to composition andtemperature, thereby interfering with the successful and proper fillingof the mold cavity.

Therefore, one of the principal objects of my invention is to provide amolten metal feeding tube that prevents the molten material fromsolidifying at the communicating orifice of the shot cylinder or well.

A further object of this invention is to provide a molten materialfeeding tube that transfers very little heat from the furnace to theshot cylinder or mold.

A still further object of this invention is to provide a molten materialfeeding tube that materially aids in the successful and proper fillingof the mold cavity.

A still further object of this invention is to provide a molten materialfeeding tube that eliminates the solidifying of the molten material atthe communicating orifice of the shot well or cylinder thereby not onlykeeping the orifice open, but also permitting the use of a cooling meansfor the shot well or cylinder and its piston. A still further object ofthis invention is to provide a molten material feeding tube that greatlyreduces the initial impact shock of the molten material intermittentlypassing therethrough.

More specifically, the object of my invention is to provide an insulatedmolten material feeding tube that imparts to its discharging moltenmaterial a spiral impetus.

A still further object of my invention is to provide a molten materialfeeding tube that is economical in manufacture and durable in use.

These and other objects will be apparent to those skilled in the art.

My invention consists in the construction, arrangements, andcombination, of the various parts of the device, whereby the objectscontemplated are attained as hereinafter more fully set forth,specifically pointed out in my claims, and illustrated in theaccompanying drawings, in which:

FIG. 1 is a longitudinal sectional view, taken on line 11, FIG. 2, of mymolten metal feeding tube means detachably secured to a shot cylinder;

FIG. 2 is a sectional view of my device taken from line 22 of FIG. 1,and more fully illustrates its construction;

FIG. 3 is a sectional view of my feeding tube taken from line 33 of FIG.1;

FIG. 4 is a longitudinal sectional view of a modified form of structureof my material feeding tube;

FIG. 5 is a cross-sectional view of the upper portion of the feedingtube taken on line 55 of FIG. 4, and

FIG. 6 is a plan view of the feeding tube taken from line 66 of FIG. 4.

3,137,903 Patented June 23, 1964 As hereinbefore indicated, my feedingtube is particularly adapted to modern casting machines such asdescribed in my co-pending application on 2. Vacuum Casting Machinefiled November 4, 1957, and bearing Serial Number 694,315, now PatentNo. 3,121,926. In most such machines there is a shot cylinder and rampiston for injecting the molten mass into the die cavity. A materialsupply tube leads from the furnace having the molten material vat to theinside of the shot cylinder forward of its piston. Mechanical means maybe employed to draw or force the molten material through the feedingtube. However, with casting machines of the vacuum type, the moltenmaterial is sucked through the feeding tube. In fact, with somematerials, a vacuum machine may dispense entirely with the shot cylinderand connect the feeding tube direct to the mold. In the drawings I showmy material feeding tube having its upper end communicating with theinside of a shot cylinder or well 10 and its lower end portion extendinginto the molten casting material 11 of the furnace. The numeral 12designates the entrance orifice extending through the wall of the shotcylinder. This passageway is tapered as shown in FIG. 1, i.e., itsdiameter increases as it extends outwardly through the wall of thecylinder. The numeral 13 generally designates the outer cylindrical wallof my feeding tube. The major portion of the length of this tube 13extends downwardly and laterally from the shot cylinder 10 with itslower end portion extending into the molten material 11 as shown inFIG. 1. The upper end of this tube housing 13 is adjacent to the opening12 in the bottom portion of the shot cylinder 11). I will first describethe specific structure of the feeding tube shown in FIGS. 1, 2 and 3.The numeral 15 designates a simple insulation inside the tube housing 13and which, in fact, protrudes beyond the upper end of the tube housing13 as shown in FIG. 1. Any suitable insulation material that would notbe affected by the molten casting material may be used, such as acomposition of aluminum and silica or the like. Irnbedded in the upperend of this insulation and in the upper end of the tube housing 13 is anozzle generally designated by the numeral 16. This nozzle 16 has adischarge opening or orifice 17 and a circular chamber 19 communicatingwith and directly back of the opening 17. This circular compartment 19is concentric with the opening 17 and has a diameter substantiallygreater than that of the diameter of the opening 17. This nozzle 16 hasits outer reduced end protruding beyond the open top end of the tube 13,but its periphery is completely embraced by insulation 15. That part ofthe insulation that protrudes beyond the open end of the cylindricalhousing 13 tapers inwardly as it extends forwardly in order to properlyengage and conform to the hole 12 of the shot cylinder 10. The numeral2t designates a lug on the under upper end portion of the cylindricalhousing 13. The numeral 21 designates an ordinary C-clamp having its capscrew 22 engaging the other side of the cylinder 10 and its lower enddetachably hooked over the lug 20. By this arrangement, the materialfeeding tube unit is detachably secured to the shot cylinder. A gasket23 may be used in the shot cylinder hole 12. Obviously, the metalliccylinder 13 does not directly contact the shot cylinder 10. Theinsulation 15 has a longitudinal bore 25 decreasing in diameter as itextends upwardly. The upper end of this bore 25 communicates with theouter area of the compartment 19 at a tangent thereto as shown in FIG.3. The nozzle opening 17 extends from a central part of the chamber 19along an axis through the opening 12 into the shot cylinder. Thus, theouter area of the compartment 19 which communicates with the bore 25' isoffset from the axis through the opening 12. By this tangential angle ofthe bore 25 relative to the compartment 19, molten material will enterthe compartment 19 at an angle, engage the circular wall of thecompartment 19, which will cause the molten material to rotate andspiral upwardly through the nozzle opening 17. This rotating orspiraling of the molten mass will obviously solve several problems.Firstly, it will automatically self-clean the upper end portion of thefeeding tube. Secondly, the whirling action of the molten material willkeep it successfully mixed against stratification as to compositionand/or temperatures. To further promote the whirling and discharging ofthe molten material from the feeding tube, I have provided a dome 26 toextend from the main mass of insulation into the central area of thecompartment 19 of the nozzle. This dome 26 is spaced from and directlyback of the nozzle opening 17 The point of entrance of the bore 25 intothe compartment 19 is obviously at one side of this dome 26. Even if inone cycle of a casting machine some molten metal would congeal withinthe discharge nozzle, the next cycle of whirling molten metal wouldeliminate such previously congealed metal. However, substantially all ofthe molten metal will either run into the shot cylinder or back into thefurnace. This return of the molten metal to the furnace is encouraged bythe bore 25 increasing in diameter as it extends downwardly. Theinsulation of my material feeding tube also prevents rapid chilling.Therefore, the molten material is maintained in suitable liquid stateduring the use of the casting machine. Thus, it is possible andpractical to feed molten metal from the center of the bath to the shotwell with no thought of solidification, even when starting from cold. Ittakes about one hour for the thermal tube to come up to heat on theinside, but it need never be removed once it is installed as the highlyinsulating material is not affected by the molten metal. Ordinarily themetal travels up the tube slowly and at a constant speed, but with theorifice up to the top out of the bath, the metal travels at a terrificspeed until it hits the restricted orifice and the sudden stopping ofthe metal is like a hammer blow. This would obviously ruin theinsulation, but by tapering this hole from large at the bottom to smallat the top, this impact is reduced to the degree that this material willstand up. This also explains to a degree why the bath level does notaffect the size of the shot since the time element for the metal toreach the orifice is so short it is negligible. Furthermore, by myconstruction the metal cylindrical housing 13 will not unduly transferheat to the shot cylinder. This makes possible the auxiliary cooling ofthe shot cylinder if desired. If desired, the outside of the cylindricalhousing 13 may be insulated.

As before indicated, FIGS. 4, 5, and 6 show a modified structure andwhich has the advantage of better drain back into the furnace. Themodified structure also has the outer tube housing 13, the insulation 15and the passageway 25, decreasing in diameter as it extends upwardly.It, however, does not have the ring 16. Instead I imbed in the upper endof the tube 13 and in the insulation a cone-shaped ceramic insert nozzle30. The upper open end 31 of this nozzle 30 discharges the moltenmaterial into the shot cylinder or mold as shown in FIG. 4. The openbase of the cone-shaped nozzle insert communicates with a cavity 32. Theupper end of the passageway 25 communicates with, but at a tangent to,the cavity 32 as shown in FIG. and FIG. 6. This arrangement of partsgives a whirling or spinning action to the molten material as shown bybroken lines in FIG. 6. Also, by the structure shown in FIG. 4, themolten material in the feeding tube will not be trapped, but will drainproperly back into the furnace. The ceramic cone-shaped nozzle isexcellent in resisting high temperatures and is of long life. Thenumeral 35 designates a metal tip or ring in the tapered opening of theshot cylinder to protect the ceramic insert 30.

Some changes may be made in the construction and arrangement of mymolten metal feeding tube for metal casting machines without departingfrom the real spirit i and purpose of my invention, and it is myintention to cover by my claims, any modified forms of structure or useof mechanical equivalents which may be reasonably included within theirscope.

I claim:

1. A molten metal feeding tube for use in feeding molten metal from amolten metal supply reservoir to a shot cylinder of a molding machinehaving an opening in one wall thereof, said molten metal feeding tubecomprising an axially elongated outer tubular wall, insulating meansextending through the entire inside of said outer tubular wall, meansproviding a chamber in said insulating means at the end of said outertubular wall adjacent said shot cylinder, said chamber being providedwith a smaller discharge orifice leading from a central part of saidchamber along an axis through said opening into said shot cylinder, anda passage in said insulating means opening into said reservoir andextending along the feeding tube and having a portion entering saidchamber in an area ofiset from said axis through said opening, saidpassage portion having a longitudinal axis which intersects a chamberwall and is spaced from said axis extending through said opening tocushion the impact of the charge of metal drawn through and dischargedfrom the feeding tube and to maintain the homogeneous composition andtemperature of the charge.

2. A molten metal feeding tube for use in feeding molten metal from amolten metal supply reservoir to a shot cylinder of a molding machinehaving an opening in one wall thereof, said molten metal feeding tubecomprising an axially elongated outer tubular wall, insulating meansextending through the entire inside of said outer tubular wall, a nozzlemember embedded in said insulating means at the end of said outertubular wall adjacent said shot cylinder and providing a chamber andhaving a discharge orifice smaller than said chamber leading from acentral part of said chamber along an axis through said opening intosaid shot cylinder, and a passage in said insulating means opening intosaid reservoir and extending along the feeding tube and having a portionentering said chamber in an area offset from said axis through saidopening, said passage portion having a longitudinal axis whichintersects said chamber wall and is spaced from said axis extendingthrough said opening to cushion the impact of the charge of metal drawnthrough and discharged from the feeding tube and to maintain thehomogeneous composition and temperature of the charge.

3. A molten metal feeding tube as set forth in claim 2 wherein saidnozzle member is ceramic.

4. A molten metal feeding tube as set forth in claim 2 wherein saidouter tubular wall is maintained in spaced relation to said shotcylinder by said insulating means.

5. A molten metal feeding tube as set forth in claim 2 wherein both saidouter tubular wall and said nozzle member are maintained in spacedrelation to said shot cylinder by said insulating means.

6. A molten metal feeding tube as set forth in claim 2 additionallyincluding a dome-like projection in said chamber on the side thereofopposite said discharge orifice and projecting along said axis towardsaid discharge orifice to induce the movement toward said dischargeorifice of the molten metal entering said chamber.

7. A molten metal feeding tube as set forth in claim 2 wherein saidpassage is of diminishing cross sectional size from said reservoir tosaid chamber.

8. A molten metal feeding tube for use in feeding molten metal from amolten metal supply reservoir to a shot cylinder of a molding machinehaving an opening in one wall thereof, said molten metal feeding tubecomprising an axially elongated outer tubular Wall, insulating meansextending through the entire inside of said outer tubular wall, meansproviding a chamber in said insulating means at the end of said outertubular wall adjacent said shot cylinder, said chamber having acylindrical inner wall surface, said chamber being provided with asmaller discharge orifice leading from a central part of said chamberalong an am's through said opening into said shot cylinder, and apassage in said insulating means opening into said reservoir andextending along the feeding tube and having a portion entering saidchamber in an area offset from said axis through said opening, saidpassage portion having a longitudinal axis which intersects saidcylindrical inner wall surface and is spaced from said axis extendingthrough said opening to cause the charge of metal to engage thecylindrical wall and spiral outwardly of said chambers through saidopening in said shot cylinder wall and thereby to cushion the impact ofthe charge of metal drawn through and discharged from the feeding tubeand to maintain the homogeneous composition and temperature of thecharge.

References Cited in the file of this patent UNITED STATES PATENTS1,732,515 Hunter Oct. 22, 1929 1,978,765 Sargent Oct. 30, 1934 2,708,298Beckes May 17, 1955 2,817,884 Ring Dec. 31, 1957 2,856,656 Ring Oct. 21,1958 2,977,649 Morton Apr. 4, 1961

1. A MOLTEN METAL FEEDING TUBE FOR USE IN FEEDING MOLTEN METAL FROM AMOLTEN METAL SUPPLY RESERVOIR TO A SHOT CYLINDER OF A MOLDING MACHINEHAVING AN OPENING IN ONE WALL THEREOF, SAID MOLTEN METAL FEEDING TUBECOMPRISING AN AXIALLY ELONGATED OUTER TUBULAR WALL, INSULATING MEANSEXTENDING THROUGH THE ENTIRE INSIDE OF SAID OUTER TUBULAR WALL, MEANSPROVIDING A CHAMBER IN SAID INSULATING MEANS AT THE END OF SAID OUTERTUBULAR WALL ADJACENT SAID SHOT CYLINDER, SAID CHAMBER BEING PROVIDEDWITH A SMALLER DISCHARGE ORIFICE LEADING FROM A CENTRAL PART OF SAIDCHAMBER ALONG AN AXIS THROUGH SAID OPENING INTO SAID SHOT CYLINDER, ANDA PASSAGE IN SAID INSULATING MEANS OPENING INTO SAID RESERVOIR ANDEXTENDING ALONG THE FEEDING TUBE AND HAVING A PORTION ENTERING SAIDCHAMBER IN AN AREA OFFSET FROM SAID AXIS THROUGH SAID OPENING, SAIDPASSAGE PORTION HAVING A LONGITUDINAL AXIS WHICH INTERSECTS A CHAMBERWALL AND IS SPACED FROM SAID AXIS EXTENDING THROUGH SAID OPENING TOCUSHION THE IMPACT OF THE CHARGE OF METAL DRAWN THROUGH AND DISCHARGEDFROM THE FEEDING TUBE AND TO MAINTAIN THE HOMOGENOUS COMPOSITION ANDTEMPERATURE OF THE CHARGE.